Information is given on crossbred calves between birth and 6 months of age belonging to 6 genetic groups--3 with 50% inheritance from Holstein, Jersey and Brown Swiss and the other 3 with 75% inheritance from 1 or 2 temperature dairy breeds. The mortality rate in 1,059 calves born was 3.87, 2.84 and 1.22% respectively under 1 month, from 1 to 3 and from 3 to 6 months of age. The mortality rate was lower in halfbreds than in crosses with 75% inheritance from temperature breeds. Season of birth, sex of the calf and birth weight did not show any significant association with mortality rate but the latter showed a definite decline with advancing age. No significant association of cause of mortality with age, genetic group and season of birth of the calves was observed. Percentage mortality was largely due to respiratory diseases in the birth to 1 minth age group while diseases affecting the digestive system resulted in more deaths in the 3 to 6 months age group.